Fig. 9.

Reduced salt tolerance in transgenic plants overexpressing GhMKK5. (A) Seed germination in the presence of the indicated NaCl concentrations. (B) Germination rates of the OE and Vec lines under normal and NaCl treatment conditions. Germination was scored daily, and the result on the MS medium with 100 mM NaCl is presented. Data are the means ±SE of three independent experiments (n=3). Asterisks (* or **) above lines indicate (highly) significant differences (*P < 0.05; **P < 0.01) according to Duncan’s multiple range test. (C) The post-germination seedling development of OE and Vec lines on MS medium containing different concentrations of NaCl. The seeds sown on MS medium for 3 d with radicle emergence were transferred onto MS medium with different concentrations of NaCl. The plates were held erect, and a photograph was taken 14 d after transfer. (D) Root length of the seedlings 14 d after transfer onto NaCl-containing plates. Data are the means ±SE of three independent experiments (n=6). Different letters above the columns indicate significant differences (P < 0.05) according to Duncan’s multiple range test. (E) Leaf discs from OE and Vec plants were infiltrated with different concentrations of NaCl (0, 100, and 200 mM). (F) Relative chlorophyll content in the leaf disks 4 d after NaCl treatments. Data are the means ±SE of three independent experiments (n=6). Different letters above the columns indicate significant differences (P < 0.05), and different italic letters indicate a highly significant difference (P < 0.01) according to Duncan’s multiple range test. OE, overexpression; Vec, vector control. #2, #4, #5, particular overexpressing lines. (This figure is available in colour at JXB online.)